Regulation and Risk Assessment of 1,4-Dioxane - Environmental Investigation and Remediation - page 311

TABLE 6.24 (continued)
Relative Risk Thresholds of Solvent Stabilizers Compounds

Carcinogenicity,
Mutagenicity, and
Genotoxicity

Stabilizer Oral Rat LD 50 Inhalation LC 50 NOAEL

1,4-Dioxane 2500 mg/kg [41] 1000 ppm for 4 h [42] 20 ppm human

inhalation, 2 h [3]

IARC group 2B:
Possibly carcinogenic to
humans; IRIS group B2:
Probable human
carcinogen [43]

Isopropyl acetate 3000 mg/kg [2] 200 ppm TCLo

human [44]

— —

tert -Butyl alcohol 3500 mg/kg [45] LD 50 14,100 ppm for

4 h [46]

Rats (oral, drinking
water); none
established [46]

A4: Not classii able as a
human carcinogen—data
on which to classify the
agent in terms of its
carcinogenicity in humans
are inadequate [16].
Two carcinogenicity
studies provide some
evidence for carcinogenicity
of tert -butyl alcohol in rats
and mice. Not mutagenic or
genotoxic [46]

Ethyl acetate 5600 mg/kg [47] 4000 ppm for 4 h [48] — —

1600 ppm for 8 h [16]

sec -Butyl alcohol 6480 mg/kg [49] 16,000 ppm rat LCLo

[50]

— —

Sources: References (shown in table by numbers in brackets) are as follows: [1] Verschueren (1983); [2] Lewis (1996); [3]
Quast et al. (1979); [4] USEPA (2006c); [5] ACGIH (2005); [6] IARC (1976); [7] Rom (1992); [8] NIEHS (2002);
[9] ACGIH (1994); [10] O'Neil (2001); [11] ECB (2000); [12] Ryan et al. (2001); [13] Waters Corporation (2007);
[14] ITII (1988); [15] Lynch et al. (1990); [16] NIOSH (1987); [17] National Toxicology Program (1988); [18]
ECB (2001); [19] OEHHA (2000); [20] UCB (2006); [21] Health Council of the Netherlands (2004); [22] Health
Council of the Netherlands (2004); [23] Machle et al. (1940); [24] NRC (1996); [25] NIH (1997); [26] CalEPA
(2007d); [27] Clayton and Clayton (1982); [28] Scala and Burtis (1973); [29] Dow Chemical Company (1992); [30]
ECB (1998); [31] Hoechst AG (1987); [32] Smyth et al. (1949); [33] Dioxolane Manufacturers Consortium (2000a);
[34] Dioxolane Manufacturers Consortium (2000b, 2000c); [35] USEPA (2007f); [36] Dow Chemical Company
(1972); [37] Smyth et al. (1962); [38] Hine et al. (1956); [39] Miller and Quast (1984); [40] USEPA (2007d); [41]
JBRC (1998); [42] Drew et al. (1978); [43] Ernstgård et al. (2006); [44] von Oettingen (1960); [45] ACGIH (1991);
[46] USEPA (2007e); [47] Clayton and Clayton (1993); [48] Snyder (1992); [49] Windholz et al. (1983); and [50]
NIOSH (1992).
Notes: IARC, International Agency for Research on Cancer; IRIS, USEPA's Integrated Risk Information System; LCLo,
lowest published lethal concentration. See Table 5.2 for a complete listing of toxicity thresholds for 1,4-dioxane;
LC 50 , median lethal concentration, that is, the concentration required to kill half the members of a tested population
within the specii ed time period; LD 50 , median lethal dose, that is, the dose required to kill half the members of
a tested population; NOAEL, No Observable Adverse Effect Level, that is, the level of exposure at which an
organism in the exposed population experiences no increase in adverse effects; TCLo, lowest published toxic
concentration.